My diesel fuel is not going back to the fuel tank, it's being reused by the fuel pump

Pcar993

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Southern CA
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I just bought a used jetta TDI, equiped with vegi oil tank in the trunk. My diesel fuel is not going back to the fuel tank, it's being reused by the IP due the the new fuel hose layout for burning vegi oil. The reason why is so that vegi oil wont go into the fuel tank. Is that OK? I mean VW engineers had some sort of reason for the return diesel fuel to run back to the fuel tank. Granted I live is So Cal. Should i change it so that the diesel fuel goes back to the fuel tank like it was stock?
 
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Pcar993

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dieselthis said:
no switching valve?
It has One 3-way solenoid valve which is used to change from Diesel to WVO, and another manual 3 way valve to switch from the fuel going back to the diesel fuel tank to the fuel being reused by the IP. Right now, its set so that the fuel is being reused back to the IP. The guy told me to not to mess with the manual 3-way valve so that the WVO wont go to the diesel fuel tank.

Hope this makes sense.
 

philngrayce

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I think you should have your whole fuel system(s) looked over. Sounds like it may be an inadequate conversion, and could well be doing your car harm.
 

dieselthis

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none yet, but work on alot of them.
so you physicaly got to stop the car and get out open the hood and turn a valve for this system to work correctly?why not get 1-6port or another 3-port and have in switch when you switch fuel. and i think the reason for the closed loop when on veg is for temp. reasons. all that is to much work. being in so.cal. why not just do a single tank and mix.or even run just on veg.i have a few cars out there that only use veg. one car i had i ran it on 80 % used motor oil and maybe 20% pump diesel and ran great no excessive smoke either
 
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dieselthis

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none yet, but work on alot of them.
its to bad cause where i am at we have a fueling dispenser that pumps wvo that has been heated and filtered down to 2micron and we pump right into the stock tank.granted these cars have heaters and heatexchangers. they are true grease cars and the best part under 2 bucks a gallon
 

Lug_Nut

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The diesel fuel would normally be pulled in by the injector pump at a much greater volume than the injectors need. The unused diesel fuel would be returned to the diesel tank. This flow of relatively cool fuel from the tank keeps the injector pump cool and lasting longer.
The WVO has to be heated to nearly 200 to approach the viscosity of diesel fuel. It would be difficult to keep up with the heating of the same volume of WVO if the recirculation system were retained so most WVO kits delete the return to tank and instead send the warmed oil back into the pump. Less cool oil from the WVO tank means warmer WVO into the pump.
I guess that if your WVO is free you can afford to deal with overheated pump failures.

If YOU will be using WVO most of the time, then the time spent on diesel will be less. Follow the seller's instructions.
If you'll be using petrodiesel or biodiesel that don't require heating, then restore the original factory return line routing, remove the WVO junk, and hope that you have stopped the pump damage while there's still enough life left in it for you to get adequate use from it.
 

oilhammer

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There are just too many to list....
Pcar993 said:
I just bought a used jetta TDI, equiped with vegi oil tank in the trunk. My diesel fuel is not going back to the fuel tank, it's being reused by the IP due the the new fuel hose layout for burning vegi oil. The reason why is so that vegi oil wont go into the fuel tank. Is that OK? I mean VW engineers had some sort of reason for the return diesel fuel to run back to the fuel tank. Granted I live is So Cal. Should i change it so that the diesel fuel goes back to the fuel tank like it was stock?
Yes, they also had some sort of reason for requiring #2 Diesel as fuel for your car. ;)

The reason the fuel is in a loop is because the fuel is not just what powers the engine, but also what cools and lubricates the fuel system. This is why so many WVO cars have repeated pump failures.

I would recommend, since you live in a warmer climate, that your extra fuel system include a way to make it loop back. Dual 3-way valves will accomplish this.

I too recommend you have a trusted someone look over your conversion, don't assume it is "good to go" as is.

I'd also make sure the system has a proper filter of some sort.
 

UFO

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Sounds like you have an older version of the "Golden Fuel System" conversion, aka Greasel. It's substandard. I wouldn't run it in an old iron Mercedes, let alone a TDI.
 

vwcampin

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philngrayce said:
I think you should have your whole fuel system(s) looked over. Sounds like it may be an inadequate conversion, and could well be doing your car harm.
Couldn't agree more. Sounds like it might be a single 6 port valve and not a 3 port. Overall it sounds like an inadequate conversion that I wouldn't trust. Can you post up some pictures?
 

Pcar993

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Thanks for all the help. Here are some pics of it. I tried to label them so that its easier to understand where all these hoses are going to. I hope i used teh correct verbage.








 
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oilhammer

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There are just too many to list....
God what a [typical] mess.... :rolleyes:

And of course, the pump has already been replaced. That is what the little white VW logo with the 2 arrows going around it is, Volkswagen's symbol for reman.

How many miles are on that car?
 

UFO

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Do not EVER run biodiesel without replacing those fuel lines. They will disintegrate and badly plug your filters and injection pump.
 

Pcar993

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oilhammer said:
God what a [typical] mess.... :rolleyes:

And of course, the pump has already been replaced. That is what the little white VW logo with the 2 arrows going around it is, Volkswagen's symbol for reman.

How many miles are on that car?
138k Which pump are you referring to?
 

oilhammer

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There are just too many to list....
The shiney newish injection pump right atop the engine. Read my first post in this thread, and Lug Nut's above it. Notice how we both mentioned WVO cars eating injection pumps? Well, yours already has.

See that little white paint stamp that is clearly visible atop the pump in one of your pics? That is the VW 'reman' symbol. That pump is a replacement, it is not the one the car rolled out of the factory with. And it probably won't be the last replacement, either. :(
 

vwcampin

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Not sure who manufactured that kit, although I think UFO might be right about it being an old Greasel conversion. After looking at the pictures I would advise a major rework of the system if you really want to use it and have the time to dedicate to making it work. Otherwise pull it out and put it back to stock. There are a lot of issues with this one.

  • I see what looks like a coolant line going to the tank in the trunk, but no other heat transfer sources?? If the only heat is coming from the WVO in the tank, uh-oh:eek: Is there something we can't see? HIH, heat exchanger?
  • What is in the trunk in the plastic bin? On first glance it appears to possibly be a filtering device to transfer WVO from the dumpster to the tank? If so, then who knows how much crappy WVO this car has consumed:( Do not continue this as a filtering method if the PO did this.
  • In the engine compartment, while a mess of wires and hoses, what concerns me most is the manual valve. Unless the PO stopped, popped the hood, manually turned the 2nd valve, then flipped the switch to the first valve, thus purging the fuel loop, every time the PO drove on WVO they ended up cold starting on WVO when they started the car again.
Starting the car on at least a mixture of cold WVO and diesel, the inability to purge the WVO completely out of the fuel loop, thus leaving WVO in the IP, running a two tank system that doesn't sufficiently heat the WVO, and probably running inadequately filtered and dewatered WVO certainly led to the IP being replaced among other issues.
 

Pcar993

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oilhammer said:
The shiney newish injection pump right atop the engine. Read my first post in this thread, and Lug Nut's above it. Notice how we both mentioned WVO cars eating injection pumps? Well, yours already has.

See that little white paint stamp that is clearly visible atop the pump in one of your pics? That is the VW 'reman' symbol. That pump is a replacement, it is not the one the car rolled out of the factory with. And it probably won't be the last replacement, either. :(
Its shinny because i just cleaned it with motor spray right before i took that picture. I can barely see that stamp. Do you have a picture of a reman IP with that stamp so i can see what a new stamp looks like? Thanks!
 

oilhammer

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There are just too many to list....
It is clear enough to me in your picture. The little white round thing, right on top of the pump. I can see it clearly in the 4th pic down.
 

Pcar993

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vwcampin said:
  • I see what looks like a coolant line going to the tank in the trunk, but no other heat transfer sources?? If the only heat is coming from the WVO in the tank, uh-oh:eek: Is there something we can't see? HIH, heat exchanger?
  • What is in the trunk in the plastic bin? On first glance it appears to possibly be a filtering device to transfer WVO from the dumpster to the tank? If so, then who knows how much crappy WVO this car has consumed:( Do not continue this as a filtering method if the PO did this.
  • In the engine compartment, while a mess of wires and hoses, what concerns me most is the manual valve. Unless the PO stopped, popped the hood, manually turned the 2nd valve, then flipped the switch to the first valve, thus purging the fuel loop, every time the PO drove on WVO they ended up cold starting on WVO when they started the car again.
The coolant lines are touching the WVO line all the way back to the tank. So i guess its HOH? No other heat exchanger except for the HOH and the one going to the WVO tank.

In the plastic bin, its an elec. pump connected to 2 filters which sucks WVO from the dumpster to make it easier.

It does loop around the IP to burn off all the WVO so that way the next start wont be burning WVO. The engine has never been started on cold WVO and the manual switch was always left so that it has always been looping the IP instead of going back to the diesel fuel tank which worries me because of all that heat going back to the IP. What do you think of that?
 

Pcar993

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oilhammer said:
It is clear enough to me in your picture. The little white round thing, right on top of the pump. I can see it clearly in the 4th pic down.
Thanks, so i guess it has a reman pump and it's LOUD!
 

Pcar993

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oilhammer said:
Sound like baseball cards in a bicycle spoke? :eek:
hahaha not quite there yet :)
It sounds like old bearings that are going bad. Or sounds like a jet of water.
 

UFO

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Pcar993 said:
It does loop around the IP to burn off all the WVO so that way the next start wont be burning WVO. The engine has never been started on cold WVO and the manual switch was always left so that it has always been looping the IP instead of going back to the diesel fuel tank which worries me because of all that heat going back to the IP. What do you think of that?
In warmer temperatures, the recirculating diesel could become a problem. The other issue is the size of the loop. It holds a lot of fuel, so you could run many miles on a switchover and still have a good percentage of oil in the pump when you shut down.

This is most definitely an old greasel design with the manual bleed/looped return. They had a proprietary hose on hose scheme with two coolant lines and a 5/16" PEX fuel line as the sole source of heat. Of course looping the return will keep more heat in the oil.

I second the recommendation you scrap most of this if you are to continue with vegetable oil. TsTDI has an excellent writeup on how to do a TDI vegetable oil in this forum; take it to heart.
 

vwcampin

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Pcar993 said:
The coolant lines are touching the WVO line all the way back to the tank. So i guess its HOH? No other heat exchanger except for the HOH and the one going to the WVO tank.-Sorry to be the bearer of bad news, but that is incredibly inadequate, even in SoCal. There is no way the WVO is getting anywhere close to 160F before being injected. At minimum I would insulate all of the WVO lines and add a FPHE.

In the plastic bin, its an elec. pump connected to 2 filters which sucks WVO from the dumpster to make it easier.-As long as it isn't going from those filters into the tank! It goes without saying that any oil coming out of a dumpster should be taken only after getting the permission of the dumpster owner (ie. not necessarily the restaurant)

It does loop around the IP to burn off all the WVO so that way the next start wont be burning WVO. The engine has never been started on cold WVO and the manual switch was always left so that it has always been looping the IP instead of going back to the diesel fuel tank which worries me because of all that heat going back to the IP. What do you think of that?-I think the IP is certainly being started on a mixture of cold WVO and diesel. Think of how long takes for all of that WVO in the fuel loop to be used up before it is replaced with diesel. You would need to be driving miles and miles and miles after switching back to diesel in order to burn that off. My opinion would be that if someone installed and operated a inadequate 2 tank WVO kit in their car, then they probably aren't driving an extra 10-20 minutes on diesel before they shut down to ensure there is no WVO is left in the lines.
The minimum for a decent 2 tank conversion will have two, 3 way valves so that during a purge cycle, you send all of the WVO back down the WVO line to the tank and out of the fuel loop. Takes about 30 seconds on a standard VW conversion and it is still recommended to drive on diesel for some distance after that.

Your best bet is to disconnect the WVO system for now and return the diesel fuel lines to stock and take an assessment of the situation. 138K, and your second IP is loud means something is wrong;)
 

Pcar993

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I just took out all the WVO parts. I bought this car 2 days ago, so i personally did not do the conversion. Thanks for all the input.
 

vwcampin

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Pcar993 said:
I just took out all the WVO parts. I bought this car 2 days ago, so i personally did not do the conversion. Thanks for all the input.
I think you made a wise decision. Clean up the WVO tank and filter along with the pump and dumpster pump stuff and throw it up on Craigslist if you don't want it. Someone will definitely buy that stuff.
 

Pcar993

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vwcampin said:
I think you made a wise decision. Clean up the WVO tank and filter along with the pump and dumpster pump stuff and throw it up on Craigslist if you don't want it. Someone will definitely buy that stuff.
Thanks, will do, the tank is in good shape, it needs a 2nd 3-way solenoid valve, and completely new heat exchangers. Too much work for me :)
 

T'sTDI

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oilhammer said:
Sound like baseball cards in a bicycle spoke? :eek:
You must have the hearing capability of a dog to be able to hear injection pump noises over combustion noises :rolleyes:
 

T'sTDI

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Pcar993 said:
I just took out all the WVO parts. I bought this car 2 days ago, so i personally did not do the conversion. Thanks for all the input.
If your still interested in converting your car the right way, I recommend you read my guide thread in this forum. It will provide a lot of insight and things to consider.


Removing that kit was the best decision you could have made. I assure you no one runs a kit like that on this forum with any appreciable amount of success.

*
 
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